Various systems are available for the analysis of liquids, for example, body liquids which need to be quantitatively analyzed with respect to specific ingredients. One such system known as the Paramax Analytic System is fully shown and fully described in U.S. Pat. No. 4,528,159 (Liston) issued Jul. 9, 1985. Such analysis systems generally include a probe which enters the sample container, such as a test tube, either through the open top thereof or by temporarily entering through the closure, for example, by puncturing a rubber stopper to form a temporary opening. See, for example, U.S. Pat. No. 4,951,512 (Mazza et al.) issued Aug. 28, 1990.
Reusable probes that are used to deliver aliquots from successive containers such as blood collection tubes or liquid reagent vessels are a source of intra-sample carryover or contamination. In order to minimize contamination and carry-over between samples, it has been conventional to flush the probe with a diluent liquid such as water, for example, as described in the Liston patent. Another technique shown, for example, in U.S. Pat. No. 3,266,322 (Negersmith et al.) issued Aug. 16, 1966, has entailed aspiration of air through the probe by means of a vacuum pump or the aspirating pump used to withdraw the sample liquid from the sample container. Such aspiration, however, introduces the possibility of drawing the unwanted carry-over contaminants deeper into the tubing and apparatus which comprises the sampling system. It has also been proposed to utilize a separate probe wash sleeve through which a pressurized rinse liquid is flushed. See for example U.S. Pat. No. 4,756,201 (Uffenheimer) granted Jul. 12, 1988. In light of these existing probe wash systems, a need has continued to exist for an improved method and apparatus for effectively cleaning such probes.